WHILE DOING REPAIR WORK ON A VIBRATING DECK FROM A READ-SCREENALL, THEY LOWERED THE DECK ON THE FLOOR WITH 1 SIDE RESTING ON AN I-BEAM THAT WAS RAISED OFF THE FLOOR BY A SHAKER SPRING UNKNOWN TO THE WORKERS. WHEN HE WENT TO UNHOOK A CABLE THE SPRING POPPED/SNAPPED IN HALF CAUSING THE I-BEAM TO FALL TO THE FLOOR AND HIS LEFT FOOT WAS SMASHED UNDER THE I-BEAM.